In a communication system, several solutions are proposed in order to reduce delay in a signaling plane and a user plane. The technical solutions include: reducing a scheduling period of an RACH (random access channel, Random Access Channel), reducing a period of a PUCCH (physical uplink control channel, Physical Uplink Control Channel), reducing processing delay of a UE (User Equipment, user equipment) and an eNB (Evolved Node B, evolved node B), and using a CB (Contention Based, contention based) resource for uplink information.
The use of the CB resource for uplink information enables a small amount of data to be fast and effectively transmitted when there is no dedicated uplink transmission resource. The CB resource is not dedicated to a single UE, and can be used by all UEs in a cell.
A method for using a CB resource for uplink transmission is that: an eNB notifies, through a dedicated identifier CB-RNTI (Contention Based Radio Network Temporary Identifier, contention based radio network temporary identifier), all UEs in a cell of a contention based resource grant, and after detecting the CB resource, the UEs may perform uplink transmission on the CB resource. Especially, in a case of low network load, a user can implement uplink transmission of data as soon as possible through CB resource allocation.
After receiving the uplink information, if the uplink information is correctly decoded, an eNB feeds back an ACK through a PHICH (Physical Hybrid-ARQ Indicator Channel, physical hybrid-arq indicator channel), and if the uplink information is not correctly decoded, the eNB feeds back a NACK through the PHICH. This feedback method may cause that a UE with conflict also receives an ACK, thereby resulting in mistakenly decision of correct transmission. As a result, loss of this part of UE data or retransmission delay may be caused.